Starting system for compression ignition engines



Feb. 13, 1940. A. w. BACH 2,190,348

STARTING SYSTEM FOR COMPRESSIONIGNITION ENGINES Filed June 3, 195a 2Sheets-Sheet 1 Feb. 13, 1940. A. w. BACH 2,1905348 STARTING SYSTEM FORCOMPRESSION IGNITION ENGINES Fil ed June 3, 1938 2 Sheets-Sheet 2 I II-7200150? Patented Feb. 13 1944) PATENT OFFICE STARTING SYSTEM FORCOMPRESSION IGNITION ENGINES and w. Bach, Chicago, 111., assignor toIntcrnational Harvester Company, a corporation of New Jersey ApplicationJune 3, 1938, Serial'No. 211,622

3 Claims.

' This invention relates to a Starting system for compression ignitionengines. More specifically, it relates to a construction in which afuel, pump is utilized to supply a heavy fuel for operation 6 on theDiesel cycle or a volatile fuel for operaw of auxiliary combustionchambers whereby the engines may be operated on a volatile fuel withspark ignition. It is to a starting system of this type that the presentinvention relates. I

The principal object of the present invention $0 is to use a fuelinjection pump normally operative to supply a heavy fuel for operationon the Diesel cycle with compression ignition for supplying a volatilefuel during a starting period of operation on low compression with sparkignition. 25 A secondary object is to interconnect the controls forshifting from low to high compression for cutting out the supply ofvolatile fuel and for changing the supply point of the fuel from theregular injection nozzle to the auxiliary combus 0 tion chamber.

Other more specific objects, such as the arrangement and actuation ofthe various valves and control mechanisms will be apparent from thedetailed description to follow.

35 In the drawings,

Figure 1 is an end view of an engine incorporating the-invention withthe cylinder head and the upper portion of the cylinder shown insection;

Figure 2 is an enlarged sectional view taken on a transverse verticalplane through the top of the fuel pump shown in elevation in Figure 1;and,

Figure 3 is a section taken on the line 33 of Figure 2.

In the drawings, an engine block III isshown broken away at the top by avertical transverse section to show a cylinder liner II and a piston l2.A cylinder head I3 of a conventional construction is mounted on the topof the block I0. A space between the top of the piston l2 and thecylinder head forms a combustion chamber 14 for operation on the Dieselcycle. -A precombustion cup assembly I5 is mounted in the cylinder head.A precombustion chamber it, formed in said assembly, is provided with anoutlet passage [1 (01. 123-182) V 1 which communicates with thecombustion chamber l4.

.A fuel supply line I! communicates with a conduit l9 extending throughthe precombustion cup assembly to the precombustion chamber It.

A discharge valve 28 controls the discharge of fuel into theprecombustion chamber I6. Said valve is held in seated position by aspring 2l until the pressure in the line has reached the de- 4 siredpressure. In any nomle, this pressure must m be sufficient to dischargeagainst the pressure existing in the precombustion chamber It. 'Thenozzle and precombustion chamber construction have been shown somewhatdiagrammatically and have been only briefly described. This constructionis conventional and may .be of any known type. V

A fuel pump casing 22 is mounted on a bracket 23 at the side of theengine block ID. A head member 24, mounted on the pump casing 22,supports the cylinders of the pump and contains all 'of the valvemechanism'which regulates actuation of the pump. a

Referring to Figure 2, a pump cylinder 25 isformed with a flanged topportion 26, which fits 25 in the bottom of a vertical bore 21 formed inthe member 24. An-injecting piston 28 is mounted for reciprocation inthe cylinder 25, being op erated in timed relation withthe engine crankshaft by any suitable mechanism. A valve cage 29 is mounted in the bore21. Said cage is formed with a passage 30 communicating with a conduit3|, which supplies fuel to the injection pump. The member 29 is formedwith a discharge opening 32, which is controlled by a spring pressed 3:;

discharge valve 33. Said valve controls delivery of fuel to a dischargepassage 34, which communicates through a fitting with the dischargeconduit l8, previously described.

An inlet chamber 36 is formed in the member 4 24, with which the passage3| communicates.

: Said chamber is in communication with a Diesel fuel supply reservoir31 formed at the top of the member 24 by a cover 38. The communicationis formed by a threaded fitting, a sleeve 41:, 5

and a valve cage 4| A valve 42 is fitted at the lower end of the cage4|, permitting the intake of fuel under suction on the intake stroke ofthe piston 28. The valve 42 is maintained in closed position during thedischarge stroke of the piston 4 by a spring 43.

Fuel is supplied to the reservoir 31 by a conduit 44. A valve 45,operable to cut off the supply of fuel through the conduit 44 isoperable by a lever 48 connected thereto.

Means are also provided for supplying a more readily volatile fuel tothe supply chamber 36. Said means consists of a fitting 41 having acentral opening therethrough. Flow of fuel through said opening iscontrolled by a valve 48, the stem of which extends outwardly andcarries at the outer end an abutment disk 49. A spring 58, fitted at oneend against the fitting 41 and at the other end against the disk 49,acts to normally maintaimthe valve 48 in closed position.

A cup-like member 5| is fitted against the side wall of the member 24 to"form a fuel supply chamber around the fitting 41. A fuel supply conduit52 is connected with the member 5| to supply a readily ignitible fuelthereto.

A pivot pin 53 connected to an operating lever 54 extends into themember 5| and carries within said member a lever arm in the form of aspring 55. Said spring has a' curved end portion fitted between theouter end of the spring 58 and the inner end of the disk 49. Byoperating the lever 54, tension may be relieved on the spring 58 wherebyfuel will be drawn from the conduit 52 rather than from the heavy oilsupply reservoir 31.

The lever arm 54 is connected by a link 56 with the lever arm 46,-previously described. Said arm is in turn connected by a link 51 with alever arm 58 mounted on a rock-shaft 59. Said rock-shaft extendstransversely across the engine, being rotatably mounted in suitablebearings. As will be noted, the, shaft is mounted in an extension member68 mounted at the top of the cylinder head l3. The shaft 59 also carriesat its outer end an operating lever 6|, by means of which the operatormay manually shift from operation on the Otto cycle to operation on theDiesel cycle. The -mechanism for this shaft has not been shown in detailas it is old in the art, as shown in the Johnston Patent No. 2,032,755of March 3, 1936.

In order to lower the compression, the shaft 59 carries a spiral worm62, which engages the teeth of a worm gear 63 mounted on alongitudinally arranged shaft 64. Said shaft carries a cam 65 operableto engage the top end of a valve stem 66. Said valve stem is slidablymounted in a guide 61 extending into an auxiliary compression chamber 68formed in the cylinder head. Said chamber communicates with thecombustion chamber l4 by means of an opening 69. The valve stem 66carries a valve 18 operable to open and'close the passage 69, wherebythe compression'ratio of the engine may be altered.

A spark-plug 1| is mounted in the auxiliary compression chamber 68.Means have not been shown for supplying current to the spark-plug 1|, asany conventional timing mechanism may be employed.

An auxiliary injection nozzle assembly 12 is mounted in the wall of theauxiliary chamber 68 for supplying, a fuel thereto, which is readilyignitib'le by spark ignition means. A conduit 13 is connected with thenozzle assembly and with a conduit 14, communicating by means of asecond conduit 15, both formed in the precombustion chamber assembly,with the Diesel fuel supply conduit. IS. A valve 16 is positioned tocontrol the flow of fuel through the conduit 15. The stem of said valveextends-outwardly through a fitting 11, being normally maintained inclosed position by a spring 18.

A lever arm 19, pivotally mounted on a bracket 88, is engageable withthe stem of the valve 16 to open said valve for the fiow of fuel to theconduit 14 during the starting period. The lever arm 19 is connected tothe change-over linkage by means of a lever arm 8| and a link 82,whereby the valve 16 will be opened when the shift in fuel supply andcompression ratio is made.

The drawings show the engine in condition for operation on the Dieselcycle with the injection of heavy fuel by the fuel pump and firing ofthe fuel charge by compression ignition. The shift will now be describedfor putting the engine in condition for starting on low compression withspark ignition.

The operating lever 6| is moved to rotate the shaft 59. By rotationofthe shaft in the direction indicated by the arrow in Figure 1, the cam65 moves downwardly, opening the valve 18 and putting the auxiliarycompression chamber 68 in communication with the combustion chamber l4,thereby lowering the compression ratio of the engine to a point where itcan be manually cranked. When the shaft 59 is rotated, the lever arm 58moves downwardly simultaneously, moving the lever arms 46 and 54downwardly. By these actuating means, the valve 45 is closed, cuttingofi' the supply of heavy oil to the reservoir. Simultaneously, tensionon the spring 58 is reduced, permitting opening of the valve 48 uponsuction created by the intake stroke of the piston 28. It will beunderstood that, with the valves in this position, the more readilyvolatized and ignitible fuel supplied through the conduit 52 will bedelivered by the injection pump through the discharge conduit |8. Inconnection with the description of this invention, only a singlecylinder has been considered. It will be understood that the injectionpump 22 would function the same for a multiple cylinder engine, therebeing an independent injection piston for each cylinder of the engine.

When the lever 46 is moved downwardly in the shift for starting, thelink 82 operates to move the lever 19 inwardly, thereby opening thevalve 16. As the injection valve 28 of the Diesel fuel supply system isheld by the spring 2| to open only upon a high pressure in the fuelsupply I line, and as the injection nozzle 12 is constructed to openupon a relatively low pressure in the injection line, opening of thevalve 16 by-passes the fuel from the injection nozzle leading into theprecombustion chamber l6 to the nozzle assembly 12, delivering into theauxiliary compression chamber. The fuel delivered to said chamber isignited by the spark-plug 1| fired in timed relation with respect to thestroke of the engine piston l2.

By the means above described, the engine is I converted to the Ottocycle and the Diesel supply pump is utilizedto supply the fuel foroperation on lower compression with spark ignition. The shift to Dieseloperation is made when the engine has been warmed up sufficiently andhas attained the speed of rotation sufiicient to ro-- all modificationsfalling within the scope of the appended claims.

What is claimed is:

1. In combination, an engine having a main combustion chamber and afirst valve for admitting heavy fiuid for normal compression ignition,and an auxiliary combustion chamber adapted to be connected'with themain'combustion chamher on starting and a second valve for admitting a.volatile starting fluid for lower compression and spark ignition, a pumpconnected with both valves and having a single plunger functioning tosupply the proper fluid to the two valves, and means for connecting theauxiliary combustion chamber with the main combustion chamber and forcausing the pump to supply volatile starting fluid to the second valve.

, 2. In combination, an engine adapted to operate normally on heavy fuelandhaving a first valve for admitting heavy fuel and a second valve foradmitting a slight fuel, a pump having a single plunger for feedinglight and heavy fuels, a first conduit connecting the pump and the firstvalve, a second conduit connecting the first 0on duit and the secondvalve, valve means for closing off the second conduit, sources of heavyand combustion chamber with a valve for admittingheavy fuel and anauxiliary combustion chamber adapted to be connected with the maincombustion chamber for starting and having a valve therein for admittinglight starting fuel, a pump having a single plunger for feeding lightand heavy fuels, a first conduit connecting the pump and the firstvalve, a second conduit connecting the first conduit and the secondvalve, valve means for closing off the second conduit from the firstconduit, sources of heavy and light fuels connectable with the pump, andmeans for simultaneously connecting the auxiliary and main combustionchambers, for opening the valve means connecting'the first and secondconduits, and for connecting the pump with the source of light fuel.

ABEL W. BACK.

